ISHS Acta Horticulturae 451: VI International Symposium on Integrated Canopy, Rootstock, Environmental Physiology in Orchard Systems
STUDY OF GROWTH ANALYSIS, WATER RELATIONS, GAS EXCHANGE, AND CARBON PARTITIONING IN ONE PLUM SPECIES DURING WATER STRESS AND RELIEF |
| Authors: | L. Lombardini, James A. Flore, John D. Everard, M. Tattini |
| Keywords: | drought stress, plum, rootstock, carbon partitioning |
| Abstract:
One-year-old plants of Prunus insititia (St. Julian), a species native to Europe and Asia and commonly used as rootstocks for plum, were subjected to three different watering regimes: well watered (Control, CT = field capacity), 50%, and 25% (Mild Stress, MS, and Severe Stress, SS, respectively) of the water received by control plants. Treatments were imposed and maintained for 14 days, followed by 2 weeks of rewatering. Shoot growth and total leaf area were affected by the stress, with a reduction proportional to the increasing level of stress and to the length of the time that the stress was maintained. After 14 days, shoot growth had completely stopped. Control assimilation rate (A) values were maintained on 7.7 μmol m-2 s-1 while stress treatments were 2.2 and 1.9 μmol m-2 s-1 CO2 assimilated, for MS and SS, respectively. Predawn leaf water potentials at day 14 of stress were -1.0 MPa in the SS plants, versus -0.4 of the controls. Leaf ABA increased after 14 days of stress, MS and SS had 16- and 18-fold the control values, respectively. The results of 14C-labeling indicated an increase in the [14C]sorbitol/[14C]sucrose ratio in SS-treated plants. This was confirmed by the analysis of nonstructural carbohydrate pools, where the sorbitol concentration was 60% higher in the stressed plants than in the control. The data collected in our experiment are not enough to support the accumulation of sorbitol as an adaptation to stress conditions, but certainly exhort further analysis in this direction. | |
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